


Work of Friction

by khrome



Category: Undertale (Video Game)
Genre: Alternate Universe - Underswap, Dry Humping, Fontcest, Grinding, M/M, Monster Heat, Praise Kink, Sexual Frustration, US!Sans, Underswap Papyrus, Underswap Sans, Undertale AU, also i am a terrible writer so theres that, i hate myself only a lottle, i no longer fear death, this is my first dirty work, us!papyrus - Freeform
Language: English
Status: Completed
Published: 2016-04-24
Updated: 2016-04-24
Packaged: 2018-06-04 04:39:12
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings, No Archive Warnings Apply
Chapters: 1
Words: 1,049
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/6641734
Author URL: https://archiveofourown.org/users/khrome/pseuds/khrome
Summary: <blockquote class="userstuff">
              <p>Sans needs a hand...<br/>Papyrus offers a leg.</p><p>(based off this fontcest drawing by http://bones-n-boners.tumblr.com/ )<br/>//NSFW// http://bones-n-boners.tumblr.com/post/143332801969/bones-n-boners-who-did-this-to-me-who</p>
            </blockquote>





	Work of Friction

**Author's Note:**

> can i die after this? it feels weird, this is my first ever smutfic and im trying to die with at least a little of my dignity intact.

Sans shuffled around his room, pacing back and forth between the window and the door. Maybe walking around would help him calm down, maybe opening the window would cool him off, maybe sitting still would help him think straight.

“guhh… nothing is working!” Sans grumbled under his breath and pulled his neckerchief down away from his heated face. Why is it so hot in here?

Sans had been using his computer to browse around on some Napstaton fan blogs when he stumbled across a very talented art blog. There was amazing fan art of his idol, but he soon found some more... raunchy fan art. Sans had felt apprehensive about viewing such lewd pictures, but surely nobody would know, right? Sans scrolled for hours, unknowingly waking a fire in his bones that was starting to become a little painful.

Sans slumped onto his bed in frustration. He glanced down at the result of his excited magic; a bright, glowing blue ecto-cock had formed right in his pants, and it just wouldn’t go away. Sans brought his hand right above it, shaking nervously. 

“hah… pap… pap will know what to do… he always knows what to do…”

Sans had been in heat before, and Papyrus had helped him relieve the tension once or twice… Sans huffed and walked toward the door; thinking about that was not helping.

Maybe if Sans asked nicely, Papyrus could take the edge off this aching.

\---------------------

Papyrus sat slumped on the couch, lazily flipping through channels on the TV; nothing good on, might as well play something for white noise to fall asleep to… A small noise upstairs alerted him to Sans slowly emerging from his room and descending the stairs… Why was he walking like that? His hands clung to his shirt in front of him, holding it in front of his crotch.

“Hey bro, you wanna watch some-“ Papyrus took a small intake of breath. Sans shifted uncomfortably.

Papyrus’ gaze flicked down to the obvious bulge in Sans’ pants, softly glowing blue.

Papyrus felt the magic in his bones stir slightly; he turned off the TV and looked toward Sans, a light dusting of orange on his cheeks.

“Uh, you okay?”

Sans shivered and spoke softly; lifting his shirt and clutching instead to his neckerchief.

“papy… it’s back again…” Sans voice started to tremble as he failed to find the right words. Just ask for help! The magic throbbed and Sans let out a whimper.

“c-can… can i…” Tears began to form in Sans eye sockets, he jumped in surprise when Papyrus sat up straighter on the couch.

“Sans… You know what to do.”

“p-papy…”

“Come here.”

Papyrus smiled gently and patted his leg, motioning for Sans to come forward. Sans crawled onto the couch and carefully swung his leg over Papyrus’ so that he was not straddling one femur. He did not sit down completely, waiting for papyrus to say something.

“Sit down.” Papyrus’ expression was pulled back in a smirk, his sockets half-lidded. He summoned a little bit of magic to make his lap softer to sit on. Sans slowly sank down on his femur.

“ah! nnn… hah… mmh…” Sans steadied himself and tried not to twitch and shake.

“You can move now…”

Papyrus leaned back and watched as Sans began to drag his crotch up and down along his leg. Sans hunched over and groaned into Papyrus’ jacket, picking up the pace and filling the room with shuffling noise.

“Woah woah… Slow down there…” Papyrus lifted Sans face; he was already sweating small droplets and his face was bright blue. Sans sat up and began to grind in a downward motion, slow and hard. A wet spot already permeating the front of his pants, Sans whined.

“That’s a good boy.”

Sans clutched at Papyrus’ leg and continued to slowly grind on it, panting and gasping between his moans of relief. Papyrus watched every moment with interest, and decided to exercise his control of the situation.

“Lift up your arms. Don’t lean on them anymore.”

Sans gave him a pleading look; when Papyrus returned the stare, Sans followed his instruction and lifted his arms by his sides, arching his back and pressing his crotch even further into Papyrus’ leg. The new angle brought more delicious friction.

“ohhh gu- gah! p-papyy… itss s-so… g-goood uhnnn~ ah!” Sans punctuated each word with a sharp thrust, his smaller frame bouncing up and down. 

“You’re doing so well Sans, keep going.”

Sans screwed his eyes shut and Papyrus knew he was getting close.

“Sans.” Papyrus wrapped his arms around his brother, pulling him in tighter.

“You can go faster now.” Papyrus muttered in a low voice next to Sans’ head. He carefully bounced his leg up to meet Sans’ thrusts, earning another groan from the smaller skeleton.

“papy! pah- ah! papyy!” Sans clutched at the back of Papyrus’ jacket as he quickened his pace; desperately moving his whole body up and down. Sans grunted with each movement, throwing his head back, eye lights unfocused, drool leaking from the corner of his open mouth.

“papy papy papy im- ah! im gunna-! gunna-! c-c-cumm~!!!”

Sans cried out, lurching into Papyrus and burying his face. His hips stuttered as he clung to Papyrus like a lifeline, whole body twitching while he came in his pants. The throbbing heat finally sated.

Papyrus hummed and ran his fingers over Sans’ spine, gently bouncing his leg, helping Sans ride out the orgasm.

The room fell quiet again as Sans stopped to catch his breath; the wet spot on his pants now soaked with cum, even leaking onto the cloth of Papyrus’ shorts.

“Do you feel better bro?”

Sans brought his other leg up onto the couch and sat cradled in Papyrus’ arms.

“so good… so warm…” Sans sighed and rested his skull on his brother’s shoulder. 

“Warm? Hmm. Sounds like you’re just getting started…Don’t worry bro. I’ve got a whole other leg for you to try out~” Papyrus chuckled and Sans let out an indignant huff.

“papy! don’t tease me like that…”

In truth, Papyrus was actually doing everything he could to control his own magic. His magic stirred in the bottom of his pelvis, pulsing and aching. Sans’ movements… His smell, his noises… That would fuel Papyrus’ fantasies for weeks.

**Author's Note:**

> well i hope that wasn't totally awkward or vague. again, this is my first dirt so be gentle with me im new to this.
> 
> edit: you can find me on tumblr- http://bigbitchbot.tumblr.com/


End file.
